1. Field of the Invention
This invention relates to apparatus for applying to a glass pane a plastic strip, which is adhesive on two mutually opposite, parallel side faces and comprises a plastic material, a moisture-absorbing substance and a metal strip that extends between said two side faces and in the longitudinal direction of the plastic strip, which plastic strip is applied to said glass pane to extend continuously along the periphery of said glass pane at a predetermined distance from the edge of said pane.
A plastic strip which has been applied at one adhesive side face to a glass pane by means of such apparatus constitutes a spacer, and a second glass pane can be applied to and forced against the second adhesive side face of the plastic strip to form an insulating glass pane. The plastic strip used for that purpose is substantially rectangular in cross-section and is made in an extrusion process. The metal strip embedded in the plastic strip serves to stiffen the latter and is preferably corrugated in its longitudinal direction so that the compressive strength of the plastic strip in a direction which is transverse to the adhesive side faces and the flexibility of the plastic strip will be promoted. The moisture-absorbing substance which is incorporated in the plastic strip prevents in the complete insulating glass pane a condensation of enclosed moisture on the inside surfaces of the insulating glass pane.
2. Description of the Prior Art
Compared with spacer frames which have been used before and consist of tubular metal rods and contain in their cavity a moisture-absorbing substance, such as molecular sieves, and which before their insertion between two individual glass panes are coated on both sides with an adhesive composition, such as polyisobutylene, spacers made of such plastic strips afford the advantage that the need for apparatus for making and coating metallic spacer frames is eliminated.
The extruded plastic strips have previously been applied to a glass pane by means of a hand-held applicator, which is supplied with the plastic strip from a supply roll and which is moved along the edge of the glass pane. But such a manually performed operation is not desirable in an insulating glass production line which is automated in other respects.